The present invention relates to a process for the manufacture of floor and/or wall coverings. More particularly, this invention relates to a novel process for manufacturing floor and/or wall coverings incorporating an inclusion of material such as fragments of PVC or other materials compatible with the covering to be manufactured; such materials being generally referred to as "pebbles". The present invention also relates to a floor or wall covering produced by this process as well as an apparatus for manufacturing the novel floor and wall covering.
U.S. Pat. No. 4,467,007 discloses a process for the manufacture of a covering material for external use. An adhesive, onto which pebbles of different particle size are successively applied, is deposited on a web; the adhesive is dried, excess pebbles are removed and the product thus obtained is covered with a sealing product. However, in the covering described in U.S. Pat. No. 4,467,007, there is no smoothing by melting and the covering has an excessive roughness which permits the deposition and accumulation of dirt. It is therefore unsuitable as a floor covering, since the hollows between the pebbles are not filled in with a synthetic material; and since no compacting operation is provided at the end of the process. Moreover, this process makes it necessary to employ two successive heat treatment stages.
German Patent No. GB-A-938,411 relates to a covering having a mosaic surface appearance. This covering is produced from a process comprising the steps of deposition of mosaic components, spaced apart from one another onto a web. If desired, interposed between the web and the mosaic components is an adhesive consisting of an acrylic resin. This is followed by heat setting treatment and then deposition of a fusible PVC powder in the interstices enclosed between the various mosaic components in order to bind them to each other by melting of the resin powder. However, particularly in the case where they are employed as a floor covering which is subject to high stresses, these mosaic components run the risk of delaminating away from the wear layer, particularly because of the heterogeneous nature of the adhesive employed.
As in the process of U.S. Pat. No. 4,467,007, the technique of the German Patent also involves the use of two successive heat treatment stages. In the first stage, the mosaics are exposed, directly and without protection, to direct heating which runs the risk of causing partial melting of the corners or ridges of the mosaics, thus "rounding-off" their asperities, which results in a relatively undesirable aesthetic appearance.
U.S. Pat. No. 3,584,096 discloses a process for the manufacture of a synthetic film having the appearance of suede leather. However, this process is unsuitable for the manufacture of a floor covering incorporating inclusions of a fusible material and permitting a wide variety of decorative patterns.
U.S. Pat. No. 3,466,223 describes a process for the manufacture of a synthetic floor covering having good dirt resistance, comprising a relatively thick, flexible base layer including PVC granules and a dirt resistant upper layer. The various layers are obtained by deposition of PVC powders, the upper layer having a particular composition. However, this process is unsuitable for the manufacture of a floor covering permitting many variations in the development of the decorative pattern. Furthermore, it is fairly costly, because of the deposition of two successive and different layers of PVC powder.
U.S. Pat. Nos. 3,359,352, 3,239,364, 2,232,780, 4,212,691 and 3,754,065 disclose other processes for the manufacture of floor or wall coverings, also incorporating inclusions of materials The processes are nevertheless complicated, are generally not suitable for the use of "pebbles" which are not readily fusible and do not permit many variations in the decorative patterns produced.